In 2019, some manufacturers and pharmacies halted Zantac sales over concerns that its active ingredient, ranitidine, degraded over time to form a chemical called NDMA. While NDMA can be present in low levels in food and water, research has found it causes cancer in larger amounts. The U.S. Food and Drug Administration (FDA) in 2020 pulled Zantac and its generic versions off the market, triggering a wave of lawsuits.